Submitted to: Medicine and Science in Sports and Exercise
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/25/2003
Publication Date: 3/18/2003
Citation: TREUTH, M.S., SHERWOOD, N.E., BUTTE, N.F., MCCLANAHAN, B., OBARZANEK, E., ZHOU, A., AYERS, C., ADOLPH, A., JORDAN, J., JACOBS, D.R. VALIDITY AND RELIABILITY OF PHYSICAL ACTIVITY MEASURES IN AFRICAN-AMERICAN GIRLS FOR GEMS. MEDICINE AND SCIENCE IN SPORTS AND EXERCISE. 2003. v. 35. p. 532-539. Interpretive Summary: Reliable and valid measures of physical activity in young children are needed. This study was designed to test 2 self-report methods against 2 activity monitors in 8 to 9 year old African-American girls. Each girl wore a CSA accelerometer and a pedometer for 4 consecutive days. Girls completed on 2 occasions a 24-hour physical activity questionnaire (GAQ) of what they did yesterday and usually, and a 3-day computerized self-report record called the Activitygram. The reliability of the methods was acceptable, except for the pedometer. The reliability was determined by the intraclass correlations (ICC) for the CSA (ICC=0.37, P<0.0001), pedometer (ICC=0.08, P=0.094), Activitygram (ICC=0.24) (P=0.005) and GAQ for physical (R=0.80, P<0.0001) and sedentary (R=0.3 to 0.5, P<0.005) activities. Using the CSA accelerometer as the "gold standard," the validity of the methods was low. Correlations assessing validity of the self-report measures and pedometer against CSA accelerometer were low for activity assessed from a single day, but higher when multiple days were used. Self-report methods need further development for improved reliability and validity in young African-American girls.
Technical Abstract: Purpose: To determine the reliability and validity of physical activity monitors and self-report instruments suitable for young African-American girls. Methods: A validation study was conducted by the Girls Health Enrichment Multi-site Studies (GEMS) research team to compare an accelerometer, the criterion method,against a pedometer and 2 self-report instruments for assessing physical activity in African-American girls, age 8 to 9 years. Girls (n=68) attended two clinic visits spaced 4 days apart. Each girl wore a MTI/CSA accelerometer (used as the criterion standard for validity), and a pedometer simultaneously for 4 consecutive days. Girls completed on 2 occasions a 24-hour physical activity checklist of yesterday and usual activities, including sedentary activities (GEMS Activity Questionnaire, GAQ), and a 3-day computerized self-report instrument (Activitygram). Results: Girls were (mean+/-SD) 9.0+/-0.6 years old and had a mean BMI of 19.4 kg/m**2. Reliability measured by intraclass correlations (ICC) and Pearson correlation coefficients (R) was calculated for the MTI/CSA (ICC=0.37, P<0.0001), pedometer (ICC=0.08, P=0.094), Activitygram (ICC=0.24) (P=0.005) and GAQ for physical (R=0.80, P<0.0001) and sedentary (R=0.3 to 0.5, P<0.005) activities. Significant Pearson correlations between the CSA and the other instruments, as a measure of validity, were observed for the 4-day average pedometer score (R=0.47, P<0.0001), the 3-day average Activitygram score (R=0.37, P=0.002), and the average of the two yesterday and the two usual GAQ activity scores for a subset of 18 physical activities questions (R=0.27, P=0.03, and R=0.29, P=0.02, respectively). The MTI/CSA was uncorrelated with single day scores from the 3 other instruments. Conclusion: The reliability of the instruments tested was acceptable, except for the pedometer. Correlations assessing validity of the self-report measures and pedometer were low and tended not to be significant for activity assessed from a single day, but higher and significant when averages of 2 to 4 days were used. Self-report instruments need further development for improved reliability and validity.